In the above purpose it is currently conventional to employ fixed elbow pieces, e.g. in various process pipelines. Such fixed pipelines call for a shutdown of the process and a disruption of the pipework in the event that, for any reason, a change of location for a pipework is desired. However, depending on how the support of a pipework is arranged, it is in some cases possible to move a pipework sufficiently in operations calling for minor displacements.
However, a particularly outstanding problem today exists in association with fixed pipelines intended for process washing, in which context the purpose to wash an industrial process, such as a process apparatus included in the basic equipment of a pulp or paper mill, by means of a wash pipe present within the same and rotating e.g. around its longitudinal axis. The wash pipe has its washing fluid supplied, preferably according to the principle shown e.g. in FIG. 5, in its entirety by way of the interior of itself and a drive unit rotating it for delivering the washing fluid further to a target by spraying or in a like manner through nozzles present in the wash pipe.
Especially in solutions of the above type it is inconvenient to execute the washing process for a process apparatus, which proceeds, according to the principle shown e.g. in FIG. 5, in several longitudinal directions. At present, such a washing process requires that several spaced-apart wash pipes, along with drive units and washing fluid pipeworks therefore, be mounted on various surfaces of a process apparatus.
For example, Finnish patent No. 107,589 discloses another method and apparatus intended for process washing, according to the principle of which at least two washing fluid supply systems are arranged by way of the interior within one and the same wash pipe for enabling operation of each supply system, such as spraying of washing fluid and/or movement of the supply system, by means of a control assembly in a manner independent from each other.
Accordingly, it is inconvenient today to implement an elongated pipeline, especially as a process washing apparatus rotating around its longitudinal axis, having a mobility in several directions or else in anticipation of its required mobility, e.g. due to maintenance operations applied to the actual process apparatus . In such cases, the required extra equipment currently results in expensive investments, plenty of necessary service and maintenance operations and required space. The above problems are further acerbated when using e.g. process washing lines according to the above-cited Finnish patent, comprising at least two flow paths nested within and separated from each other for process washing fluid.